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<head>
    <meta charset="UTF-8">
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    <title>Document</title>
    <script src="./jquery.js"></script>
</head>
<body>
    <div id="box">你真是个天才</div>
    <script>
      var obj={
        fn:function(){
            $('#box').css('background','red')
            return obj
        },
        fn2:function(){
            $('#box').addClass('add')
            return obj
        },
        fn3:function(){
            $('#box').click(function(){
                alert('总能来点惊喜')
            })
        }
      }
      obj.fn().fn2().fn3()
    </script>
</body>
</html>